<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
		<title></title>
	</head>
	<body>
		
		<span id="app-3" v-once>这个将不会改变: {{ msg }}</span>
		
		<script type="text/javascript">
			var vm = new Vue({
				el:'#app-3',
				data:{msg:'hello'}
			})
			vm.$data.msg = 'hello ....'
		</script>
	</body>
</html>
